1. Field Of The Invention
This invention relates to clamps for securing mitered workpieces during a fabrication procedure. The invention relates more particularly to an improved miter clamp for securing mitered joints of fine wood trim workpieces during a finish trim procedure.
2. Description Of The Prior Art
On-site miter joint fine finishing generally involves initially positioning finish wood trim workpieces having miter cuts in place at a location where they are to be installed. An example of one such procedure is the installation of fine trim molding at an entrance way or door jamb. Such workpieces have a principal planar surface greater in length than the width of the workpiece and substantially greater in length than the thickness of the workpiece. Fine trim finishing generally provides for gluing together the miter cuts of the work pieces. This requires that the workpieces be maintained in relatively close assembly and accurate alignment after placement of the glue and as the glue cures. Miter clamps have previously been used for this purpose but have suffered from one or more deficiencies in use. In an on-site procedure, the finish trim workpieces are placed against a wall or door jam surface to which they are to be permanently mounted. The miter joint is therefore positioned adjacent tie and in contact with a mounting surface and, at times, close to other surfaces, as for example a ceiling surface. These relatively close space restrictions render it difficult to place and use prior miter joint clamps. Such prior art miter clamps include a clamp actuating means which provides for the application of a manual force to an edge of the clamp. In this type of clamp an adjusting arm extends in a direction generally parallel to the principal plane of the workpieces. One such clamp has been marketed by the Hartford Clamp Company of Hartford, Connecticut. In the relatively confined space in which such a clamp is being mounted, adjustment of this clamp can be either restricted or prohibited by other relatively closely positioned structural surfaces such as a wall and ceiling. Its utility is thereby limited.
Another form of clamp as described in U.S. Pat. No. 3,278,177 to W. B. Zern provides an actuating lever arm extending in a direction normal to the principal plane of the workpiece and applies a clamping force in a direction normal to the principal plane of the workpieces. This requires an extension of the workpiece beyond the mounting structure, a need which cannot be satisfied in many trim finishing procedures. Since the edge is close to the mounting surface, an adequate adjustment can only be provided with great difficulty in the relative close space available for the adjustment. Failure to properly mount the miter clamp often results in out of line or improperly aligned joints.
It is also desirable to gradually increase the clamping force applied to the workpiece, pause to remove excess glue expelled from the miter joint and continue to increase the application of force to its final level while maintaining the desired alignment. Another desirable characteristic of such a clamp is to be able to accommodate workpieces of relatively smaller and larger widths while also maintaining the desired alignment.